Bug fix for out of bounds slice access

[fulghum]

Fixes: #2684

[github-actions]

	Main	PR
covering_index_scan_postgres	1733.96/s	1760.56/s	+1.5%
index_join_postgres	242.73/s	243.72/s	+0.4%
index_join_scan_postgres	254.70/s	254.87/s	0.0%
index_scan_postgres	15.77/s	15.84/s	+0.4%
oltp_point_select	3171.45/s	3201.48/s	+0.9%
oltp_read_only	2398.57/s	2371.89/s	-1.2%
select_random_points	167.37/s	165.15/s	-1.4%
select_random_ranges	1386.52/s	1393.99/s	+0.5%
table_scan_postgres	15.41/s	15.36/s	-0.4%
types_table_scan_postgres	7.15/s	7.08/s	-1.0%

[zachmu]

LGTM!

[github-actions]

	Main	PR
Total	42090	42090
Successful	18014	18013
Failures	24076	24077
Partial Successes1	5373	5373

	Main	PR
Successful	42.7988%	42.7964%
Failures	57.2012%	57.2036%

${\color{red}Regressions (1)}$

random

QUERY:          (SELECT unique1 AS random
  FROM onek ORDER BY random() LIMIT 1)
INTERSECT
(SELECT unique1 AS random
  FROM onek ORDER BY random() LIMIT 1)
INTERSECT
(SELECT unique1 AS random
  FROM onek ORDER BY random() LIMIT 1);
RECEIVED ERROR: expected row count 0 but received 1

Footnotes

1. These are tests that we're marking as Successful, however they do not match the expected output in some way. This is due to small differences, such as different wording on the error messages, or the column names being incorrect while the data itself is correct. ↩